Coming into the 2017 season, Luis Severino was a divisive topic of conversation for Yankee fans, writers, and probably even the Yankee organization. After last season's disastrous results as a starting pitcher, resulting in his temporary demotion and part-time assignment to the Major League bullpen, Luis Severino was an enigma. Given his substantial success as a reliever during his brief appearances in that role, throwing high nineties heat to pair with a wipe-out slider, many wanted to permanently convert Severino into a reliever, thus allowing the Yankees to turn many games into six-inning affairs with Severino, Betances, and Chapman shutting the door in innings 7-9. Others pointed to Severino's age, previous success as a starter in 2017, former prospect status, and the prior quality of his change-up as reasons to believe that Severino could turn it around as a starter this season. While the sample-size is admittedly small, Severino has given Yankee fans reason to believe that he can live up to the hype he generated as a prospect. The question remains: is he a different pitcher than he was last year? Or is this early season small sample size noise? The early returns are positive.

The most oft-discussed topic regarding Luis Severino's viability as a starter is the quality and usage of his change-up. As a prospect in the Yankee system, many scouts considered his change-up his best pitch. As I noted in my Spring Training primer on the candidates for the Yankee rotation, Severino displayed a low 80's change with fade and deception dating back to the 2014 Future's Game. The pitch was hit hard early last season, and as the season progressed, the change-up was missing in action. Below is Luis Severino's pitch usage by month, courtesy of brooksbaseball.net.

Severino made an effort to throw the change early in the season, but as his results continued to lag, he almost completely ditched the pitch, despite the Yankees directives to throw it. Looking back, much of the issue can be linked to the velocity separation between the fastball and the change-up. Typically, starters have an approximate separation of 10 MPH between the fastball and change-up, and although there are exceptions to that rule, it is important to have velocity separation for the purpose of deception. The change-up is supposed to be thrown with the same arm speed as the fastball, and thus hitters' timing is thrown off by the movement and velocity separation. Here are Severino's velocity readings from last season:

Courtesy of brooksbaseball.net

Severino's change-up sat at close to 90 MPH all of last season, and only maintained 6 MPH of separation from his fastball. When Severino missed with the change, as occurred often last season, there was not enough velocity separation from his fastball to keep hitters honest and disrupt their timing.

Severino's superficial stat line has been positive in the early going (12.2 K/9, 0.9 BB/9, 6.3 H/9), and one reason has been the increased usage and quality of the change-ups he's thrown.

Courtesy of brooksbaseball.net

Courtesy of brooksbaseball.net

Through the first two starts for which we have Trackman data, Severino has thrown just enough change-ups to keep hitters off-balance, and he has also increased the velocity separation between his fastball and change.

While Severino struggled against both RHH and LHH last season, his most pronounced improvement this season has been against LHH. According to baseball-reference.com, Severino allowed a line of .261/.331/.416 for an sOPS+ (OPS+ relative league-average OPS+ split) of 101. Thus far in 2017, Severino has allowed a line of .156/.182/.281 to LHH for an sOPS+ of 27. Again, much of that improvement can be credited to proper usage of his change-up. Below are his stats for pitch usage vs. LHH in both 2016 and 2017, respectively.

Courtesy of brooksbaseball.net

Courtesy of brooksbaseball.net

Most importantly, not only has Severino increased his usage of the change vs. lefties, but he has also almost doubled his usage of the change when he is behind in the count, allowing him to even the count.

Can Severino sustain this kind of performance moving forward? I am admittedly biased given that I was in the "Severino needs a chance to start" camp, I think that assuming he continues to trust his change-up, and use it in all parts of the count as he is doing now, Severino can be a top-of-the-rotation pitcher for the Yankees this season and beyond. Given the confidence he has displayed on the mound thus far, I am inclined to believe that Severino can keep rolling right along, and confound hitters with a devestating three-pitch mix. Luis Severino in 2017 is a decidedly different pitcher than the 2016 version, and he is primed to fulfill the expectations fans, writers, and the organization placed on him as a prospect.